![]() Let’s take a look at a concrete example of where a NullPointerException might be thrown. Throwing null as if it were a Throwable value.Accessing or modifying the slots of null as if it were an array.Taking the length of null as if it were an array.Accessing or modifying the field of a null object.Calling the instance method of a null object.However, there are a few points that we ought to take into consideration. The conversions from a primitive boolean value and a Boolean object to a string are pretty similar. Format of the string and type of the resulting object is defined by the specific converter. Returns: a string representation of the object passed in. Method Detail fromString public Boolean fromString ( String value) Converts the string provided into an object defined by the specific converter. Specified by: toString in class StringConverter < Boolean >.Boolean.parseBoolean () Boolean.parseBoolean () allows us to pass in a String and receive a primitive boolean. Note that truthiness is not the same as being loosely equal to true or false. Overview In this tutorial, we'll explore the different ways we can use Java's Boolean class to convert a String into a boolean. The Boolean () function: Boolean (x) uses the same algorithm as above to convert x. Double NOT: x negates x twice, which converts x to a boolean using the same algorithm as above. Format of the returned string is defined by the specific converter. There are two ways to achieve the same effect in JavaScript. But, as we know, there are two boolean types in Java: the primitive boolean and the object Boolean. public String toString ( Boolean value) Converts the object provided into its string form. The Java API documentation on NullPointerException lists a couple of scenarios where this exception could be invoked: Converting a boolean value to a string is a simple task in Java. Therefore, a null pointer exception will occur when the code is pointing to something in memory that does not exist. Or you can do that explicitly: boolean di ( (Boolean) someObject). If you have read the Sentry answer to Is Java Pass-By-Reference or Pass-By-Value?, you might know that in Java, variables are simply pointers to objects in memory. 3 Answers Sorted by: 152 If the object is actually a Boolean instance, then just cast it: boolean di (Boolean) someObject The explicit cast will do the conversion to Boolean, and then there's the auto-unboxing to the primitive value. In Java, a NullPointerException occurs when a variable that is being accessed has not yet been assigned to an object, in other words, the variable is assigned as null.
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